Hello Kris,

This appears to be an evergreen shrub that has been allowed to grow into its full mature size, even though it seems to be more deciduous. (Most gardeners prune them significantly shorter, but occasionally a gardener will let them reach their full potential.) The foliage traits (including the type of leaf spot infection that is present in the photo) and your description of flowers and leaf color changes all suggest that this is a Red-tip Photinia, also called Fraser's Photinia (botanical name Photinia x fraseri). They are much more commonly grown as a sheared hedge, though arguably the plants tend to stay more healthy if left unpruned. Still, they are very commonly affected with this type of leaf spot infection, which can cause lots of leaf drop as a result, in addition to the bit of normal leaf shed that occurs each year (even among evergreens). Generally, the more extensive the infection (combined with any stresses, like limited root space and drought), the more leaves will shed.

This plant's location very close to the building is certainly adding to its stress, and this year's wet spring weather (despite the drought that is persisting now) led to higher levels of infection. If you want to keep the plant, rake-up fallen Photinia leaves (if possible) and dispose of them so they don't harbor the pathogen over the winter. Re-infection in future springs can still occur, but removing the infected leaf litter reduces that risk. While fungicides applied repeatedly during spring and early summer might reduce infection risk or severity, they are not recommended (nor do they always work well) and might impact pollinators or other organisms. If it's simpler and you're not keen on keeping the tree, then removing it might be best, though if it deprives the azalea pictured below of summer shade, that might stress the azalea.

The leaf litter from the Photinia, whether it was infected or not, won't cause a problem with herbs or other plantings, and fallen leaves do not significantly alter soil pH. (If you want to measure soil pH, consider having a laboratory soil test performed, which is more accurate and easier to interpret than the results of home test kits.)

Herbs require full sun (6-8 or more hours of direct sun in summer) and excellent soil drainage, as they have little tolerance for getting too wet. Make sure a planting site is far enough away from a tree or large shrub so that it won't shade the plants too much (only a few herbs do okay with less than full sun, and even then, their productivity is diminished), and far enough away from any roof downspout outlet that extra rainwater won't flood their root zones. If you lack a suitable soil site, or if there are too many shrub roots to dig through, then building a raised bed can help to provide good drainage, but don't place a raised bed over top of tree or shrub roots as burying them with all that extra soil can suffocate them.

Miri

You're welcome!